Quantitative concepts can be particularly frustrating to model and demonstrate, especially concepts such as elapsed time. One manipulative that attempts to obviate the hurdles of teaching elapsed time is the geared analog clock, which has hands that users can manipulate. While the product is effective for demonstrating a specific time, i.e., teaching the telling of time, it can be particularly confusing for students to visualize and calculate elapsed time as every full 360 degree rotation of the minute hand causes the hour hand to rotate 30 degrees.
Another manipulative currently available is a set of disks and fractional components of a disk, which represent units of time, and a circular board in which the disks can be inserted, the board being representative of an analog clock. The manipulative, however, is limited to showing elapsed time of an hour or less, and does not allow a user to choose a start and end point.
Yet another manipulative currently available is a double-sided magnetic board, which is marked with predetermined intervals of time on the board, and a plurality of rectangular magnetic pieces that are representative of time. One side of the board is representative of a.m., while the other side is representative of p.m. The board, however, does not allow users to easily transition from a.m. to p.m., as the board must be turned over.